The Collaborative International Dictionary of English v.0.48:

Refutation \Ref`u*ta"tion\ (r?f`?*t?"sh?n), n. [L. refutatio:
   cf. F. r['e]futation.]
   The act or process of refuting or disproving, or the state of
   being refuted; proof of falsehood or error; the overthrowing
   of an argument, opinion, testimony, doctrine, or theory, by
   argument or countervailing proof.
   [1913 Webster]

         Same of his blunders seem rather to deserve a flogging
         than a refutation.                       --Macaulay.
   [1913 Webster]

WordNet (r) 3.0 (2006):

refutation
    n 1: the speech act of answering an attack on your assertions;
         "his refutation of the charges was short and persuasive";
         "in defense he said the other man started it" [syn:
         refutation, defense, defence]
    2: any evidence that helps to establish the falsity of something
       [syn: disproof, falsification, refutation]
    3: the act of determining that something is false [syn:
       falsification, falsifying, disproof, refutation,
       refutal]